Pretty much any complicated machine is going to develop some mythology over time, and the automobile is no exception. Cars have been ubiquitous for more than 100 years, and seemingly with every new innovation comes a new myth that is either created or busted.

Here are the top six auto maintenance myths.

The 3,000-Mile Oil Change

The “three months or 3,000 miles” oil change interval was invented by oil manufacturers, not auto manufacturers. Even 50 years ago, most manufacturers suggested changing the oil at more like 5,000 miles. There is nothing wrong with changing it every 3,000 miles, of course, but if you look at your owner’s manual, you’ll probably see a higher number.

“Tune-Ups”

We put that in quotes because that term, as commonly understood, isn’t relevant to modern engine designs. In the old days, a tune-up involved a whole series of tasks, including changing the plugs and points and tuning the carburetor. Well, modern engines don’t have any of that stuff. Except for spark plugs. So if you as a mechanic to perform a tune-up on a car built within the last 25 years, all he’s going to do is change the spark plugs.

Premium Gas Make More Power

If we’ve said it once we’ve said it 1,000 times: Premium gasoline will do nothing extra for a car that doesn’t require it. This myth persists because the oil companies call high-octane fuel “premium” and low-octane fuel “regular,” implying one is better for the other. There is a bunch of complicated science involved with this, but all you need to know is that if your car doesn’t specifically indicate it is designed to run on premium fuel, premium fuel won’t do a single thing for you that regular won’t. That said, if your car does require premium, you’ll cause it to run worse by running regular.

Filling Your Gas in the Morning

The mythology goes like this: Since temperatures are lower in the morning, the gasoline will be more dense, meaning the parts of it that would be vaporizing during the afternoon are being pumped, as liquid, into your tank. This is nonsense. Gasoline is stored underground, and its temperature isn’t affected enough on the way to your tank for there to be any different.

Dirty Cars Get Better Mileage

This one is out there, but some people actually believe that a car caked in dirt will get better fuel economy than a clean car because of something having to do with dimples on a golf ball or whatever. The opposite is true. the dirt creates more drag. Wash your car.

Wash Your Car with Dish Soap

The thinking goes that since dish soap is great at removing oils, it’s great for cleaning your car. And it’s true: Dish soap will wash the daylights out of your car. It will remove all the dirt, and the grime, and the oils, and the wax, and it will leave your paint and the sun with nothing between them. Use less harsh soaps designed for auto finishes.

If you’ve got work that needs doing on your car, bring it to our expert technicians at Finnegan Chevrolet Buick GMC. Our technicians know the ins and outs of your vehicle, and will repair it perfectly with genuine Chevrolet parts.